Referring to FIG. 1, a socket system 100 of the prior art includes a socket 102 for coupling a plurality of pins 104 of an IC (integrated circuit) device 106 to a corresponding plurality of contact pads 108 of a circuit board 110. The pins 104 of the IC device may be arranged as an array when the IC device is implemented as a micro-pin grid array IC package, as known to one of ordinary skill in the art of integrated circuits. Each of the pins 104 of the IC device 106 is coupled to a respective one of the contact pads 108 via a respective one of the leads 112 of the socket 102. For example, a first pin 114 of the IC device 106 is coupled via a first lead 116 of the socket 102 to a first contact pad 118 of the circuit board 110, which may be a PCB (printed circuit board).
Electrical signals are routed to or from the pins 114 of the IC device 106 via the contact pads 108 of the circuit board 110 during testing or operation of the IC device 106, as known to one of ordinary skill in the art of integrated circuits. Referring to FIGS. 1 and 2, the socket 102 is mounted to the circuit board 110 with a screw mechanism 120 such that each of the leads 112 of the socket 102 makes electrical contact with a respective one of the contact pads 108 of the circuit board 110.
In addition, the IC device 106 is mounted to the socket 102 with a clamping mechanism 122 such that each of the pins 104 of the IC device 106 makes electrical contact with a respective one of the leads 112 of the socket 102. Each of the pins 104 of the IC device 106 is inserted into a respective opening within the socket 102 to make electrical contact with a corresponding one of the leads 112 of the socket 102. The clamping mechanism 122 clamps down the body of the IC device 106 (i.e., the portion of the IC device not including the pins 104) onto the socket 102.
FIG. 3 shows a cross sectional view of an example opening 124 for the first pin 114 of the IC device 106 making contact with the first contact pad 118 of the circuit board 110 via the first lead 116 of the socket 102. The lead 116 is within the opening 124 of the socket 102. In the prior art, the lead 116 is part of a two-ended pogo spring mechanism including a first pogo spring 126 disposed toward the pin 114 and a second pogo spring 128 disposed toward the contact pad 118.
Referring to FIGS. 2 and 4, when the socket 102 is mounted to the circuit board 110 and the body of the IC device 106 is clamped to the socket 102, the pin 114 is inserted into the opening 124 and makes electrical contact with the top end of the lead 116. In addition, the bottom end of the lead 116 makes electrical contact with the contact pad 118. The first pogo spring 126 is compressed and pushes the top end of the lead 116 against the bottom of the pin 114 to ensure that the top end of the lead 116 makes electrical contact with the bottom of the pin 114. Similarly, the second pogo spring 128 is compressed and pushes the bottom end of the lead 116 against the contact pad 118 to ensure that the bottom end of the lead 116 makes electric contact with the contact pad 118.
Referring to FIGS. 2 and 4, one disadvantage of the prior art socket system 100 is that the body of the IC device 106 is clamped to the socket 102. Because of the compression force on each of the pins 104 from the top end of the respective lead 116 within the socket 102, the IC device 106 is clamped to the socket 102. Such clamping force and the compression force on the pins 104 may be deleterious to the IC device 106. With advancement of integrated circuit technology, the IC device has an increased number of pins 104. A larger number of pins results in increased total compression force on the pins 104 and increased clamping force on the IC device 106. Such forces may warp and damage the structures of the IC device 106 which may lead to malfunction of the IC device 106.
In addition, in the prior art socket system 100, the top of the lead 116 makes electrical contact with the bottom of the pin 114. As a result, the electrical path length between the IC device 106 and the contact pad 118 is not minimized in the prior art socket system 100. However, a minimized electrical path length between the IC device 106 and the contact pad 118 is desired for minimizing resistance which enhances the speed performance of the IC device 106.
Thus, a socket system is desired that minimizes force on the IC device 106 and that minimizes the electrical path length between the IC device 106 and the contact pad 118.